Can We Avoid Head CT scan in Some Pediatric Patients With Head Trauma?

In a multicenter trial published in Lancet recently, Kuppermann N et al. enrolled 42,412 children (age, ≤18 years) with mild head trauma (defined as Glasgow Coma Scale score >13) to derive and validate decision rules for two separate age groups:
- those below 2 years and
- those aged 2 years and above.

In that paper, the authors highlighted the need to identify pediatric patients with very low risk of clinically important brain injuries who might not need a CT scan after all:

1. 40 - 60% of those with traumatic brain injuries seen on CT scan are from this group of patients with minor head injuries or those with GCS 14 and 15.

2. But the converse is not true - less than 10% of those with minor head injuries show traumatic brain injuries

3. Furthermore, even if there are head trauma identified, injuries needing neurosurgery are very uncommon in children with GCS scores of 14 - 15

4. The risk of radiation exposure. Ionising radiation from CT scans can cause lethal malignancies. The estimated rate of lethal malignancies from CT is between 1 in 1000 to 1 in 5000 pediatric cranial CT.

But predictive models in such cases are not new. There have been predictive models to identify low risk patients where Head CT may probably be avoided. However, in that paper, it is stated that the problems with previous predictive models:

- are limited by small sample size
- lack of validation
- no independent assessment of preverbal children (less than 2 years old)

From that study, the authors identified that:

The Decision To Avoid CT in Children with Head Trauma could be made:

A. In Children less than 2 years old if
* Normal mental status
* No scalp hematoma except frontal hematoma
* LOC<5 seconds
* Non severe mechanisms of injuries (see below for the list)
* No palpable scalp fracture
* Normal behavior

B. In Children 2 years and above if
* Normal mental status
* No LOC
* No vomiting
* Non severe mechanisms of injuries (see below for the list)
* No signs of base of skull fracture
* No severe headache

Non severe mechanisms of injuries:
# death of a passenger in the accident
# ejection of patient from the vehicle
# rollover
# pedestrian or bicyclist without helmet struck by the vehicle
# fall more than 1.5 m for children above 2 years old and more than 0.9 m for children less than 2 years
# head struck by high impact object

In the validation group of 2216 children younger than 2 years, the rule had 100% sensitivity and negative predictive value. In the validation group of 6411 children 2 years and older, the rule had 96.8% sensitivity and 99.5% negative predictive value.

Using the list of features identified, the suggested algorithm for mild head trauma in that paper:
A. In Children less than 2 years old:
Step 1:
Is the patient with altered mental status OR a palpable skull fracture: If yes - CT;
If no, then proceed to Step 2

Step 2:
Is the patient has occipital or parietal or temporal scalp hematoma OR LOC 5 or more seconds OR severe mechanism of injury OR "not acting normally" as per parent:
if yes: (use clinical judgement with the following in mind)
Observation vs CT on the basis of other clinical features include
- physician experience
- multiple versus isolated findings
- worsening symptoms of signs after emergency department observation
- age of less than 3 months
- parental preference


if not
- then CT SCAN IS NOT RECOMMENDED

B. In Children 2 years or older

Step 1:
Is the patient with altered mental status OR other signs of basilar skull #: if yes - CT

If no, then proceed to Step 2:

Step 2:
Is the patient with history of LOC OR vomiting OR severe mechanism of injury OR severe headache:

If yes, again Observation vs CT on the basis of other clinical factors including:
- physician experience
- multiple versus isolated findings (see note below)
- worsening symptoms or signs after emergency department observation
- parental preference

If no, then CT SCAN IS NOT RECOMMENDED.

Note: Patients with certain isolated findings (i.e. without other findings suggestive of traumatic brain injury) such as
- isolated LOC
- isolated headache
- isolated vomiting
- certain types of isolated scalp hematomas in infants older than 3 months
have risk of clinical important TBI (traumatic brain injuries) of less than 1%.

In general, if risk of clinically important TBI is exceedingly low, lower than risk of CT induced malignancies, then CT scans are not indicated.

In short, while using this rule may identify pediatric patients at very low risk of having clinically important TBI when ALL of the CRITERIA are fulfilled; the converse is not true. Doctors still have to use their own clinical judgment to see which patients they would order a CT scan. Nevertheless, as always, extra caution is still advisable in children younger than 3 months, in whom clinical evaluation may be less reliable.


Reference:
Kuppermann N et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: A prospective cohort study. Lancet 2009 Sep 15; [e-pub ahead of print]. (http://dx.doi.org/10.1016/S0140-6736(09)61558-0)